package org.apache.lucene.search.spans;
/**
 * Copyright 2005 The Apache Software Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import org.apache.lucene.index.Term;
import org.apache.lucene.index.TermPositions;

import java.io.IOException;
import java.util.Collections;
import java.util.Collection;

/**
 * Expert:
 * Public for extension only
 */
public class TermSpans extends Spans {
    protected TermPositions positions;
    protected Term term;
    protected int doc;
    protected int freq;
    protected int count;
    protected int position;

    public TermSpans(TermPositions positions, Term term) throws IOException {

        this.positions = positions;
        this.term = term;
        doc = -1;
    }

    @Override
    public boolean next() throws IOException {
        if (count == freq) {
            if (!positions.next()) {
                doc = Integer.MAX_VALUE;
                return false;
            }
            doc = positions.doc();
            freq = positions.freq();
            count = 0;
        }
        position = positions.nextPosition();
        count++;
        return true;
    }

    @Override
    public boolean skipTo(int target) throws IOException {
        if (!positions.skipTo(target)) {
            doc = Integer.MAX_VALUE;
            return false;
        }

        doc = positions.doc();
        freq = positions.freq();
        count = 0;

        position = positions.nextPosition();
        count++;

        return true;
    }

    @Override
    public int doc() {
        return doc;
    }

    @Override
    public int start() {
        return position;
    }

    @Override
    public int end() {
        return position + 1;
    }

    // TODO: Remove warning after API has been finalized
    @Override
    public Collection<byte[]> getPayload() throws IOException {
        byte[] bytes = new byte[positions.getPayloadLength()];
        bytes = positions.getPayload(bytes, 0);
        return Collections.singletonList(bytes);
    }

    // TODO: Remove warning after API has been finalized
    @Override
    public boolean isPayloadAvailable() {
        return positions.isPayloadAvailable();
    }

    @Override
    public String toString() {
        return "spans(" + term.toString() + ")@" + (doc == -1 ? "START" : (doc == Integer.MAX_VALUE) ? "END" : doc + "-" + position);
    }

    public TermPositions getPositions() {
        return positions;
    }
}
